The younger brother of the late Manfred Winkelhock, Winkelhock was raised in Waiblingen, near Stuttgart. Joachim won the 1988 German Formula Three championship, and that year's European Cup. The next year was less successful, as he tried F1 with the small AGS concern. Failing to qualify on 7 occasions, Joachim then linked up with BMW in touring cars.
His first title was the 1993 British Touring Car Championship; he next won the 1994 Asia-Pacific Touring Car Championship, and in 1995 he won the German Super Touring Championship. He also triumphed in the 1995 SPA 24 Hours, and the 1994 and 1998 Macau Guia touring car races. His last success for BMW came at Le Mans, which he won in 1999 driving their V12 LMR prototype. In 2000, he joined Opel in the new DTM, and in 2003 he announced his retirement from motor racing. He was also commonly known as "Smoking Jo", for his cigarette habit.